A Physiologic Approach to Hemodynamic Monitoring and Optimizing Oxygen Delivery in Shock Resuscitation

Influence of liberal versus conservative oxygen therapies on the hemodynamic parameters of mechanically ventilated patients with sepsis: a randomized clinical trial

BACKGROUND

There is no significant evidence verifying the efficacy of liberal versus conservative oxygen therapy on hemodynamics in patients with sepsis. We investigated how liberal and conservative oxygen therapy influenced stroke volume, cardiac output, and vasopressor needs in patients with sepsis undergoing mechanical ventilation.

METHODS

This randomized clinical trial included 106 patients with an admission diagnosis of infection, a Sequential Organ Failure Assessment (SOFA) score of two points or higher and required invasive mechanical ventilation for at least 72 h. Patients were randomly assigned to one of two oxygenation strategies: liberal (n = 53) with a target SpO2 of ≥ 96% or conservative (n = 53) with a target SpO2 of 88-92%. Transthoracic Doppler echocardiography was done twice to measure stroke volume and cardiac output, initially upon enrollment in the trial and then 72 h later. The primary outcome was stroke volume. Secondary outcomes were cardiac output, vasopressor use, mechanical ventilation duration, ICU stay length, and adverse events.

RESULTS

Stroke volume and cardiac output measurements did not differ significantly between research groups after 72 h of oxygenation treatment (p = 0.459 and 0.637, respectively). Forty-five patients (84.9%) in the conservative oxygen therapy group needed vasopressors to maintain their mean arterial pressure above 65 mmHg, whereas 35 patients (66.0%) in the liberal group did (p = 0.024). A multivariate logistic regression analysis of the independent variables for vasopressor requirements revealed that patients in the conservative oxygen group were 3.83 times more likely to require vasopressors (AOR = 3.83, 95% CI: 1.31-11.18, p = 0.014) than those in the liberal group. Older patients (AOR = 1.03, 95% CI: 1.01-1.07, p = 0.038) and those with higher SOFA scores (AOR = 1.36, CI: 1.09-1.68, P = 0.005) were significantly more likely to need vasopressors.

CONCLUSIONS

Liberal or conservative oxygen therapy did not influence stroke volume or cardiac output measurements in mechanically ventilated patients with sepsis. Patients in the conservative oxygen group were more likely to require vasopressors than those in the liberal group.

TRIAL REGISTRATION

This study was approved by the Ethics Committee of Aswan University Hospital (approval number: Aswu/460/5/20) (registration date: 05/05/2020) and registered on ClinicalTrials.gov (NCT04824703) (03/30/2021).

Time to Calm the Fick Down? A Systematic Review and Meta-Analysis of Thermodilution Compared to Direct Fick in Tricuspid Regurgitation

Background

Many clinicians consider thermodilution (TD) as a means to measure cardiac output (CO) to be unreliable in patients with tricuspid regurgitation (TR). No systematic appraisals of this clinical issue have been conducted. We hypothesized that the level of inaccuracy of using TD in patients with TR, compared to the direct Fick (DF) method, to determine CO, is overstated.

Methods

We performed a systematic search of 6 major literature databases for the period from 1946 to July 2023. Studies were included if they included CO measurements determined with both TD and the DF method in patients with vs without TR. Meta-analysis of the correlation between the measurements determined by TD vs the DF method was performed, stratified by the presence of TR.

Results

A total of 1064 studies were identified, of which 8 met the inclusion criteria. Four of the studies were included in the pooled analysis. The presence of TR did not affect the correlation between CO measurements determined by TD vs the DF method (moderate-to-severe TR: r = 0.90, 95% confidence interval 0.76, 0.96; mild or no TR, r = 0.86, 95% confidence interval 0.71, 0.93). Many studies had high levels of heterogeneity and risk of bias.

Conclusions

The accuracy of CO measurements made using TD, compared to the gold-standard DF method, may not be meaningfully affected by the presence of moderate-to-severe TR. Given the high levels of heterogeneity and risk of bias of the included studies, these findings should be replicated in a modern cohort.

Prediction of fluid responsiveness in spontaneously breathing patients with hemodynamic stability: a prospective repeated-measures study

Evaluating fluid responsiveness with dynamic parameters is recommended for fluid management. However, in hemodynamically stable patients who are breathing spontaneously, accurately measuring stroke volume variation via echocardiography and passive leg raising is challenging due to subtle SV changes. This study aimed to identify normal SV changes in healthy volunteers and evaluate the precision of hemodynamic parameters in screening mild hypovolemia in patients. This prospective, repeated-measures, cross-sectional study screened 269 subjects via echocardiography. Initially, 45 healthy volunteers underwent a fluid challenge test, the outcomes of which served as criteria to screen 215 ICU patients. Among these patients, 53 underwent additional fluid challenge testing. Hemodynamic parameters, including medians of maximum velocity time integrals (VTImaxs), peak velocity of VTImax (PV), internal jugular vein diameters (IJVD), and area (IJVA) were repeatedly measured first at a 60° upper body elevation (UBE), second in a supine position, third at UBE, fourth in a supine position, and lastly in a supine position after fluid loading. The hemodynamic responses to the position changes were compared between 83 fluid non-responders and 15 fluid responders. Fluid responsiveness was defined as fluid-induced medians' change of VTImaxs (fluid-induced median VTImax change) ≥ 10%. None of the healthy volunteers showed the mean value of repeatedly measured medians of VTImaxs ≥ 7%, following either UBE position (UBE-induced median VTImax change) or fluid loading (fluid-induced median VTImax change). UBE-induced median VTImax and PV changes were significantly correlated with fluid responsiveness (p < 0.001, AUC 0.959; p < 0.001, AUC 0.804). The significant correlations were demonstrated via multivariable analysis using binary logistic regression (p = 0.001, OR 90.1) and the correlation coefficient (R2 = 0.793) using linear regression analysis. UBE-induced median VTImax changes (≥ 11.8% and 7.98%) predicted fluid-induced median VTImax changes ≥ 10% and 7% (AUC 0.959 and 0.939). The collapsibility and variation of IJVD and IJVA showed no significant correlation. An increase in the mean value of medians of repeatedly measured VTImaxs transitioning from an UBE to a supine position, effectively screened mild hypovolemia and demonstrated a significant correlation with fluid responsiveness in spontaneously breathing patients maintaining hemodynamic stability.

Tactics of infusion therapy in patients with acute destructive pancreatitis: a narrative review

INTRODUCTION: Infusion therapy is the main method of correcting pathological changes that occur during the phase of “aseptic” inflammation in acute pancreatitis. OBJECTIVE: Summarize current data on infusion therapy regimens in patients with acute destructive pancreatitis, the advisability of using various infusion solutions and options for monitoring the effectiveness of therapy. MATERIALS AND METHODS: The study was carried out in accordance with international reporting requirements for reviews (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). The search was carried out in the following Internet search engines Pubmed and Cochrane Controlled Clinical Trials Register. To select articles, a literature reference search method was also used. The search strategy did not include restrictions on language, article type, or date. RESULTS: The analysis of literature data revealed two approaches to infusion therapy. The initial interest in “aggressive (4 liters per day or more)” infusion therapy regimens in the first 24 hours of the disease has now been replaced by a trend towards less “aggressive” regimens due to the publication of works on the high incidence of various complications (progression of organ dysfunction, local complications). When considering the qualitative composition of infusion therapy, preference should certainly be given to crystalloids. Basic monitoring of infusion therapy should include non-invasive methods: heart rate, blood pressure, diuresis rate. CONCLUSIONS: The analysis demonstrated different approaches to the tactics of infusion therapy in this category of patients. further research into the effectiveness and safety of infusion therapy, taking into account the varying severity of acute pancreatitis, the possibility of the influence of the qualitative composition of the infusion on the course of this disease and the formation of recommendations for initial and maintenance infusion therapy based on the principles of personalized medicine.

The impact of ECPELLA on haemodynamics and global oxygen delivery: a comprehensive simulation of biventricular failure

BACKGROUND

ECPELLA, a combination of veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) and Impella, a percutaneous left ventricular (LV) assist device, has emerged as a novel therapeutic option in patients with severe cardiogenic shock (CS). Since multiple cardiovascular and pump factors influence the haemodynamic effects of ECPELLA, optimising ECPELLA management remains challenging. In this study, we conducted a comprehensive simulation study of ECPELLA haemodynamics. We also simulated global oxygen delivery (DO2) under ECPELLA in severe CS and acute respiratory failure as a first step to incorporate global DO2 into our developed cardiovascular simulation.

METHODS AND RESULTS

Both the systemic and pulmonary circulations were modelled using a 5-element resistance‒capacitance network. The four ventricles were represented by time-varying elastances with unidirectional valves. In the scenarios of severe LV dysfunction, biventricular dysfunction with normal pulmonary vascular resistance (PVR, 0.8 Wood units), and biventricular dysfunction with high PVR (6.0 Wood units), we compared the changes in haemodynamics, pressure-volume relationship (PV loop), and global DO2 under different VA-ECMO flows and Impella support levels.

RESULTS

In the simulation, ECPELLA improved total systemic flow with a minimising biventricular pressure-volume loop, indicating biventricular unloading in normal PVR conditions. Meanwhile, increased Impella support level in high PVR conditions rendered the LV-PV loop smaller and induced LV suction in ECPELLA support conditions. The general trend of global DO2 was followed by the changes in total systemic flow. The addition of veno-venous ECMO (VV-ECMO) augmented the global DO2 increment under ECPELLA total support conditions.

CONCLUSIONS

The optimal ECPELLA support increased total systemic flow and achieved both biventricular unloading. The VV-ECMO effectively improves global DO2 in total ECPELLA support conditions.

Therapeutic Effects of Shenfu Injection in Shock

Shock is the clinical manifestation of acute circulatory failure, which results in inadequate utilization of cellular oxygen. It is a common condition with high mortality rates in intensive care units. The intravenous administration of Shenfu Injection (SFI) may attenuate inflammation, regulate hemodynamics and oxygen metabolism; inhibit ischemia-reperfusion responses; and have adaptogenic and antiapoptotic effects. In this review, we have discussed the clinical applications and antishock pharmacological effects of SFI. Further in-depth and large-scale multicenter clinical studies are warranted to determine the therapeutic effects of SFI on shock.

Reviving Hope: A Comprehensive Review of Post-resuscitation Care in Pediatric ICUs After Cardiac Arrest

This comprehensive review thoroughly examines post-resuscitation care in pediatric ICUs (PICUs) following cardiac arrest. The analysis encompasses adherence to resuscitation guidelines, advances in therapeutic interventions, and the nuanced management of neurological, cardiovascular, and respiratory considerations during the immediate post-resuscitation phase. Delving into the complexities of long-term outcomes, cognitive and developmental considerations, and rehabilitation strategies, the review emphasizes the importance of family-centered care for pediatric survivors. A call to action is presented, urging continuous education, research initiatives, and quality improvement efforts alongside strengthened multidisciplinary collaboration and advocacy for public awareness. Through implementing these principles, healthcare providers and systems can collectively contribute to ongoing advancements in pediatric post-resuscitation care, ultimately improving outcomes and fostering a culture of excellence in pediatric critical care.

Damage control surgery in emergency general surgery: What you need to know

ABSTRACT

Damage-control surgery (DCS) is a strategy adopted to limit initial operative interventions in the unstable surgical patient, delaying definitive repairs and abdominal wall closure until physiologic parameters have improved. Although this concept of "physiology over anatomy" was initially described in the management of severely injured trauma patients, the approaches of DCS have become common in the management of nontraumatic intra-abdominal emergencies.While the utilization of damage-control methods in emergency general surgery (EGS) is controversial, numerous studies have demonstrated improved outcomes, making DCS an essential technique for all acute care surgeons. Following a brief history of DCS and its indications in the EGS patient, the phases of DCS will be discussed including an in-depth review of preoperative resuscitation, techniques for intra-abdominal source control, temporary abdominal closure, intensive care unit (ICU) management of the open abdomen, and strategies to improve abdominal wall closure.

The Association Between Tachycardia and Mortality in Septic Shock Patients According to Serum Lactate Level: A Nationwide Multicenter Cohort Study

BACKGROUND

This study aimed to evaluate whether the effect of tachycardia varies according to the degree of tissue perfusion in septic shock.

METHODS

Patients with septic shock admitted to the intensive care units were categorized into the tachycardia (heart rate > 100 beats/min) and non-tachycardia (≤ 100 beats/min) groups. The association of tachycardia with hospital mortality was evaluated in each subgroup with low and high lactate levels, which were identified through a subpopulation treatment effect pattern plot analysis.

RESULTS

In overall patients, hospital mortality did not differ between the two groups (44.6% vs. 41.8%, P = 0.441), however, tachycardia was associated with reduced hospital mortality rates in patients with a lactate level ≥ 5.3 mmol/L (48.7% vs. 60.3%, P = 0.030; adjusted odds ratio [OR], 0.59, 95% confidence interval [CI], 0.35-0.99, P = 0.045), not in patients with a lactate level < 5.3 mmol/L (36.5% vs. 29.7%, P = 0.156; adjusted OR, 1.39, 95% CI, 0.82-2.35, P = 0.227).

CONCLUSION

In septic shock patients, the effect of tachycardia on hospital mortality differed by serum lactate level. Tachycardia was associated with better survival in patients with significantly elevated lactate levels.

Stroke Volume Measurements by Echocardiography and Ultrasonic Cardiac Output Monitor in Children: A Prospective Observational Cohort Study

OBJECTIVES

Stroke volume (SV) and cardiac output monitoring is a cornerstone of hemodynamic assessment. Noninvasive technologies are increasingly used in children. This study compared SV measurements obtained by transcutaneous Doppler ultrasound techniques (ultrasonic cardiac output monitor [USCOM]), transthoracic echocardiography jugular (TTE-J), and parasternal (TTE-P) views performed by pediatric intensivists (OP-As) with limited training in cardiac sonography (20 previous examinations) and pediatric cardiologists (OP-Bs) with limited training in USCOM (30 previous examinations) in spontaneously ventilating children.

METHODS

A single-center study was conducted in 37 children. Each operator obtained 3 sets of USCOM SV measurements within a period of 3 to 5 minutes, followed with TTE measurements from both apical and jugular views. The investigators were blinded to each other's results to prevent visual and auditory bias.

RESULTS

Both USCOM and TTE methods were applicable in 89% of patients. The intraobserver variability of USCOM, TTE-J, and TTE-P were less than 10% in both investigators. The SV measurements by OP-As using USCOM, TTE-J, and TTE-P were 46.15 (25.48) mL, 39.45 (20.65) mL, and 33.42 (16.69) mL, respectively. The SV measurements by OP-Bs using USCOM, TTE-J, and TTE-P were 43.99 (25.24) mL, 38.91 (19.98) mL, and 37.58 (19.81) mL, respectively.The percentage error in SV with USCOM relative to TTE-J was 36% in OP-As and 37% in OP-Bs. The percentage error in SV with TTE-P was 33% relative to TTE-J in OP-As and 21% in OP-Bs.

CONCLUSIONS

Our findings show that the methods are not interchangeable because SV values by USCOM are higher in comparison with the SV values obtained by TTE. Both methods have low level of intraobserver variability. The SV measurements obtained by TTE-P were significantly lower compared with the TTE-J for the operator with limited training in echocardiography. The TTE-P requires longer practice compared with the TTE-J; therefore, we recommend to prefer TTE-J to TTE-P for inexperienced operators.

Admission Lactate Concentration, Base Excess, and Alactic Base Excess Predict the 28-Day Inward Mortality in Shock Patients

Base excess (BE) and lactate concentration may predict mortality in critically ill patients. However, the predictive values of alactic BE (aBE; the sum of BE and lactate), or a combination of BE and lactate are unknown. The study aimed to investigate whether BE, lactate, and aBE measured on admission to ICU may predict the 28-day mortality for patients undergoing any form of shock. In 143 consecutive adults, arterial BE, lactate, and aBE were measured upon ICU admission. Receiver Operating Curve (ROC) characteristics and Cox proportional hazard regression models (adjusted to age, gender, forms of shock, and presence of severe renal failure) were then used to investigate any association between these parameters and 28-day mortality. aBE < −3.63 mmol/L was found to be associated with a hazard ratio of 3.19 (HR; 95% confidence interval (CI): 1.62−6.27) for mortality. Risk of death was higher for BE < −9.5 mmol/L (HR: 4.22; 95% CI: 2.21−8.05), particularly at lactate concentrations > 4.5 mmol/L (HR: 4.62; 95% CI: 2.56−8.33). A 15.71% mortality rate was found for the combined condition of BE > cut-off and lactate < cut-off. When BE was below but lactate above their respective cut-offs, the mortality rate increased to 78.91%. The Cox regression model demonstrated that the predictive values of BE and lactate were mutually independent and additive. The 28-day mortality in shock patients admitted to ICU can be predicted by aBE, but BE and lactate deliver greater prognostic value, particularly when combined. The clinical value of our findings deserves further prospective evaluation.

Immunomonitoring of Monocyte and Neutrophil Function in Critically Ill Patients: From Sepsis and/or Trauma to COVID-19

Immune cells and mediators play a crucial role in the critical care setting but are understudied. This review explores the concept of sepsis and/or injury-induced immunosuppression and immuno-inflammatory response in COVID-19 and reiterates the need for more accurate functional immunomonitoring of monocyte and neutrophil function in these critically ill patients. in addition, the feasibility of circulating and cell-surface immune biomarkers as predictors of infection and/or outcome in critically ill patients is explored. It is clear that, for critically ill, one size does not fit all and that immune phenotyping of critically ill patients may allow the development of a more personalized approach with tailored immunotherapy for the specific patient. In addition, at this point in time, caution is advised regarding the quality of evidence of some COVID-19 studies in the literature.